1. Field of the Invention
The present invention relates to a connector, comprising terminals, each having resilient curl portions of a generally mountain-like cross-sectional shape integrally formed respectively on opposite side edges of a base plate portion, and a connector housing having lances for engagement with the resilient curl portions. More particularly, the present invention relates to an improved connector in which the amount of displacement of the lance in an engaged condition is stabilized.
The present application is based on Japanese Patent Application No. Hei. 11-348494, which is incorporated herein by reference.
2. Description of the Related Art
A connector, used for connecting vehicle""s wire harnesses or the like together, comprises electrically-conductive female terminals of a known construction, and a connector housing of a synthetic resin for receiving the terminals.
The terminal is comprised of an electrically-conductive metal sheet, and resilient curl portions of a generally mountain-like cross-sectional shape for electrical contact purposes integrally formed respectively on opposite side edges of a base plate (see a terminal (low insertion force terminal) disclosed in Unexamined Japanese Utility Model Publication No. Hei. 6-33373).
Terminal receiving chambers for respectively receiving the terminals are formed in the connector housing. The terminal receiving chambers extend through the connector housing from a front end surface thereof to a rear end surface thereof, and terminal insertion ports are formed in the rear end surface of the connector housing, and connection ports for respectively receiving mating male terminals are formed in the front end surface of the connector housing.
A lance for retaining the terminal, received in the terminal receiving chamber, and an elastic displacement-allowing space for the lance are formed within each terminal receiving chamber. The lance has a tongue-like distal end portion. A retaining projection, projecting toward the terminal, is formed on the lance, and is disposed adjacent the distal end portion of the lance.
The retaining projection can engage the resilient curl portions of the terminal to prevent the terminal from moving in a withdrawing direction. The elastic displacement-allowing space is formed in that wall of the terminal receiving chamber on which the lance is formed. A lance displacement detection pin of a connector inspecting instrument can be inserted into the elastic displacement-allowing space through the insertion port, formed in the front end surface, to reach a position near to the proximal end portion of the lance.
The connector inspecting instrument includes the lance displacement detection pins and electrical contact pins. When the electrical contact pin is electrically connected to the corresponding terminal, it is judged that the terminal has been completely received in the terminal receiving chamber.
When the terminal is held in a half-inserted condition in the terminal receiving chamber, the lance is kept stranded on the terminal, with the retaining projection held in contact with inner slanting surfaces of the resilient curl portions, so that the distal end portion of the lance is sufficiently received in the elastic deformation-allowing space. In this condition, when the lance displacement detection pin is inserted into the elastic displacement-allowing space, this pin abuts against the distal end portion of the lance, so that the electrical contact pin can not contact the terminal, thereby detecting the half-inserted condition of the terminal.
In the above related connector, the resilient curl portions of the terminal in the connector have a generally mountain-like cross-sectional shape, and therefore the amount of displacement of the lance in an engaged condition is liable to be varied because of the adjustment of a terminal inserting force (required for inserting the terminal into the connector housing) and a load of contact of the terminal with the mating male terminal (not shown) (In the adjustment, the inclination of the inner slanting surfaces of the resilient curl portions is changed, and therefore the amount of displacement of the lance is influenced). As a result, the inspecting process, effected by the use of the connector inspecting instrument, is affected.
More specifically, if the amount of displacement of the lance in an engaged condition is small, the distal end portion of the lance may not be disposed in the elastic displacement-allowing space even when the terminal is in a half-inserted condition, and therefore there is a possibility that in the subsequent inspecting process, the lance displacement detection pin is completely inserted deep into the position near to the proximal end portion of the lance. When the lance displacement detection pin is thus completely inserted deep, the electrical contact pin abuts against the terminal to be electrically connected thereto, and therefore it is judged through the connector inspecting instrument that the terminal has been completely received in the terminal receiving chamber.
With the above problem in view, it is an object of the present invention to provide a connector in which the amount of displacement of a lance is stabilized so that the detection by a connector inspecting instrument can be effected positively.
To achieve the above object, according to the first aspect of the present invention, there is provided a connector which comprises a connector housing including a terminal receiving chamber, a metal terminal insertable into the terminal receiving chamber, the terminal including a base plate portion, a wire connecting portion formed on the base plate portion, and an electrical contact portion having resilient curl portions which extend from opposite side edges of the base plate portion and are inwardly bent to form curls thereof, a lance formed in the terminal receiving chamber, the lance having a distal end portion which extends in an inserting direction of the terminal, a retaining projection portion formed on the lance, the retaining projection portion retaining the terminal in a complete insertion state thereof to be prevented from moving in a withdrawing direction opposite to the inserting direction, and at least two projections integrally formed on the lance, the projections projecting in a width direction of the terminal receiving chamber which is perpendicular to the inserting direction of the terminal, wherein when the terminal is inserted into the terminal receiving chamber, the projections are respectively brought into sliding contact with apexes of the resilient curl portions.
In the present invention, when the terminal is inserted into the terminal receiving chamber, the lance, formed within the terminal receiving chamber, is elastically deformed by the terminal. The lance is continued to be elastically deformed by the terminal until the at least two projections, formed on the lance, slide onto the apexes of the resilient curl portions, respectively. When the terminal is thus inserted, the at least two projections are brought into sliding contact with the apexes of the resilient curl portions. When the terminal is completely inserted, the projections are disengaged from the apexes of the resilient curl portions, respectively, and the lance is restored into its original condition because of its own restoring force, and retainingly engages the terminal. The lance prevents the terminal from being withdrawn from the terminal receiving chamber.
If the terminal inserting operation is finished, with the terminal held in a half-inserted condition, the lance is kept stranded on the apexes of the resilient curl portions through the at least two projections, so that the amount of displacement of the lance is large. In a subsequent inspecting process, the half-inserted condition can be positively detected on the basis of the position of the distal end portion of the lance.
Even if the inclination of inner slanting surfaces of the resilient curl portions is changed when adjusting a terminal inserting force and a contact load, the height of the terminal from the base plate portion to the apexes of the resilient curl portions is not changed, and therefore the amount of displacement of the lance is stable. And besides, the amount of displacement of the lance in an engaged condition is large.
Preferably, the lance may be formed in a cantilever manner with respect to the connector housing to be elastically deformable. With respect to the resilient curl portions, it may be considered to have a generally mountain-like shape in a cross section thereof, and to be formed integrally with the opposite side edges of the base plate portion of the terminal. With respect to the retaining projection portion, it may be formed on a portion of the lance near to the distal end portion thereof, so that the retaining projection portion can engage the terminal to be retained in the terminal receiving chamber.
According to the second aspect of the present invention, each of the projections has a surface disposed in a plane in which a retaining surface of the retaining projection portion lies. In this case, when the lance is engaged with the terminal, the terminal is retained by the retaining projection portion and the at least two projections.
According to the third aspect of the present invention, each of the projections has a tapering surface so formed that each of the projections is decreased in thickness progressively in the withdrawing direction of the terminal opposite to the inserting direction. In this case, when the terminal is inserted into the terminal receiving chamber, the resilient curl portions of the terminal abut against the tapering surfaces, so that the terminal inserting force acts on these tapering surfaces. As the terminal is inserted, the tapering surfaces are pressed by the terminal, and therefore the lance can be easily elastically deformed. The projections will not be caught by the resilient curl portions, and therefore will not interfere with the insertion of the terminal.